PRECIPITATION

n. Pre-si2p-i2-ta'sh'n 'L .,prcecipitatio. 1. See FESTINATION. 2. In chemistry, the act or proce of forming a precipitate, [a, 38.] Fractional p. A method of separating a mixture of fatty acids by adding a small portion of the acetate of a heavy metal, which combines with a relatively larjje proportion of the le volatile acid and with a small proportion of the more volatile acid. These metallic compounds, being insoluble, are separated by filtration. The nitrate contains a higher charge of the more volatile acid, and by a repetition of the proce may be entirely freed from the le volatile acid. If the latter, on the other hand, appears in greater proportion in the precipitate, and if it is rede composed into a mixture of acids by the action of hydrochloric acid, it may again be precipitated, and the proce repeated till the precipitate contains only the le volatile acid. [B. 3, 4.] Partial p. A method of separating a mixture of two soluble salts by precipitating a portion of each and decomposing the precipitate, which is redi olved and again in part precipitated. [B, 4.] [s. 329]